Two important injection locking parameters are frequency detuning. Chaotic dynamics of semiconductor lasers for secure optical. Injection locking properties of a semiconductor laser. Modeling the effect of slave laser gain and frequency comb. The effect of optical injection locking oil on modulation dynamics of tunable laser diodes tlds is investigated. The modulation properties of an injectionlocked semiconductor laser are investigated using the rate equation formalism. Pandey centre for quantum technologies, national university of singapore, 117543 singapore, singapore m. In this letter, we use a stochastic semiconductor laser rate equation model to investigate the injection locking properties of gainswitched lasers. An alternative to injection locking involves the use of coupled laser systems, and these also have proved effective for enhancing modulation limits via the relatively fast photonphoton resonance effect 2327. Recently, optical injection locking has been proven to enhance the bandwidth and resonance frequency of directlymodulated semiconductor lasers. Furthermore, relatively lower vcsel intrinsic cutoff frequencies translated in to impossibility of achieving high bit rates. Injection locking in distributed feedback semiconductor lasers. A highpower algaas semiconductor laser was sidemode injection locked for laser cooling with frequency 0 ghz away from freerunning states. Synchronization properties of coupled semiconductor lasers subject to.
Bangor university doctor of philosophy optical effects on the. Peters abstracta rate equation model was used to model the optical. This means that the laser resonator receives some optical feedback usually with some spectral filtering. Injection locking properties of a semiconductor laser have been analyzed, taking into account the injected carrier density dependent refractive index in the active region. Locking bandwidth of two laterallycoupled semiconductor lasers. Theoretical analysis of optical injection locking in semiconductor. Intensity and phase modulations im and pm are analyzed throughout the. The injection locking properties of the slave laser were measured with saturated absorption spectrum and optical heterodyne beat technique. Amplitude regeneration of phase encoded signals using. Modelling the effect of slave laser gain and frequency.
Locking and unlocking phenomena in optically injected semiconductor lasers have been extensively studied. The modulation properties of an injection locked semiconductor laser are investigated using the rate equation formalism. Demonstration of an analog fiberoptic link employing a. Modulation properties of an injectionlocked semiconductor. May 01, 2000 a highpower algaas semiconductor laser was sidemode injection locked for laser cooling with frequency 0 ghz away from freerunning states. Surette, dag roar hjelme, member, ieee, reinold ellingsen, and alan rolf mickelson, member, ieee. The nonlinear laser equations can easily be solved. The idea of optical injection is that external light, usually of high monochromaticity, is injected into a laser in order to dictate certain properties of the lasers output light.
Strong optical injection locked semiconductor laser for high. Introduction injection locking is a particularly interesting method to reduce laser linewidth,1 enhance the modulation bandwidth,2 synchronize lasers for microwave generation3,4 or measure the linewidth enhancement factor. Semiconductor lasers types, applications, construction. Optical single sideband modulation using a semiconductor. A general equation for the complex temporal envelope of the optical field is derived. Pdf injection locking of a semiconductor laser to a multifrequency. Pdf selfinjection locking of a laser diode to a highq wgm. In semiconductor lasers, external injection produces an enormous variety of.
Section v is devoted to the proposed scheme based on the experiments and simulations. Carefully designed slave laser can inherit characteristics of the. This method, based on the principle of external optical injection locking, does not require the knowledge of the absolute value of optical injection level. The locking characteristics are determined by theamount of injected power and thefrequency difference between the master laser and slave laser. The shift is more obvious when plotted as a function of injection strength, as in figure 4. First, chirpcharacteristics of semiconductor lasers are described. Injection locking, semiconductor laser, phase noise, dfb laser 1. The properties of injection locking chaos synchronization and communication in closedloop externalcavity semiconductor lasers ecsl subject to phaseconjugate feedback pcf are investigated systematically. The study of injection locking characteristics was performed on an inas quantum dash qdash semiconductor laser for the first time. We theoretically analyze the general conditions for the injection locking, and numerically investigate the properties of injection locking chaos synchronization in the phase and. Mutual injection locking of a fibre laser and a dfb semiconductor laser l.
For example, filtered optical feedback can be provided to a. We investigate the dynamics of semiconductor lasers subject to timedelayed optical feedback from the perspective of dynamical selfinjection locking. In particular, a symmetrical lock ing band at low optical injection level is confirmed. Theoretical results concerning injection locking in complex cavity semiconductor lasers are reported. The relaxation oscillation frequency is measured to be 26. Semiconductor lasers subject to external optical injection have received a lot of attention, mainly due to applications such as injection locking 1, frewx quency stabilization 2 and chirp reduction 3. Strong optical injection locked semiconductor laser for. Note that injection locking is more than injection seeding. In this paper, the chirp of injection locked semiconductor lasers has been theoretically investigated. A rate equation model was used to model the optical filtering properties of injection locked semiconductor lasers. Modulation dynamic response of opticalinjectionlocked. The stable locking boundary map of oil tld which depends on the lasing wavelength was calculated and the tld response in different injection states was investigated.
Moreover, we investigate a recently found dynamical regime of fragmented lffs by means of a locking. Modeling the effect of slave laser gain and frequency comb spacing on the selective ampli. Locking conditions and stability properties for a semiconductor laser with external light injection j. Synchronization properties of coupled semiconductor lasers. In addition, we demonstrate a novel alloptical stabilisation technique for modelocked semiconductor lasers by combination of cw optical injection and optical feedback to. Highspeed modulation of semiconductor lasers by optical. A slaved cavity resonance and its relevant injection locking properties. Since the semiconductor laser has unique features of high gain, low facet reflectivity, and amplitudephase coupling through the \\alpha \ parameter, it is also sensitive to optical injection from a different laser. This is sometimes referred to as masterslave relationship.
Optical injectionlocking is proposed as a solution to these problems. Bangor university doctor of philosophy optical effects. The processing techniques and properties are described here in the last decade the semiconductor injection laser. Indexing terms measurement, semiconductor lasers a simple and accurate method to measure the linewidth enhancement factor u in dfb semiconductor lasers is pro posed. Especially optical injection locking has been appreciated as a useful tool for controlling and stabilizing laser oscillations. Locking and unlocking phenomena in optically injected semiconductor lasers.
Typical laser and crystalline wgm parameters and locking properties estimates. The major necessary conditions for injection locking to occur are that the input light from the. Simple analytical formulas for the width of the locking band and resulting laser linewidth are derived. We present the analysis of the selfinjection locking of a singlefrequency laser diode to a highq whispering gallery mode wgm microresonator with rayleigh backscattering.
Injection locking properties of a semiconductor laser have been analyzed, taking into account the injected carrier density dependent refractive index in. Injection locking properties of a semiconductor laser ieee xplore. In this method, one laser diode is operated as a master laser to control the injection locking and the other is operated as a slave laser. Sep 17, 2018 laser injection locking has been mainly used for amplification 38 and duplication 39,40,41,42 of lownoise laser oscillator. Mutual injection locking of a fibre laser and a dfb. Moreover, we investigate a recently found dynamical regime of fragmented lffs by means of a. Sidemode injection locking characteristics of 150 mw. It is shown that the carrier density dependent refractive index affects drastically the behavior of injection locked semiconductor lasers, giving rise to peculiar.
In this letter, we use a stochastic semiconductor laser rate equation model to investigate the injectionlocking properties of gainswitched lasers. This agrees qualitatively with the theoretical analysis in 9 and 11. Simulation of strongly injectionlocked semiconductor ring. It was found that there is an optimal slave laser current at which the crr of the slave laser is. Rp photonics encyclopedia injection locking, single.
We present the analysis of the self injection locking of a singlefrequency laser diode to a highq whispering gallery mode wgm microresonator with rayleigh backscattering. Semiconductor injection laser diodes emitting in the near infrared are now finding applications in optical fibre communication, consumer products such as digital discs, and optical recording. Optical signal inverter using injection locking of coupled. Highly tunable repetitionrate multiplication of mode. Novel measurement technique of alpha factor in dfb. Under optimised bias conditions of the slave laser, a repetition frequency tuning ratio 2% is achieved, a record for a monolithic semiconductor modelocked laser. The laser parameters are considered to be identical.
Locking conditions and stability properties for a semiconductor laser. Numerical and experimental results are presented which show the changes in the comb rejection ratio crr of an injection locked single mode laser due to the gain of the slave laser. Osa selfinjection locking of a laser diode to a highq. Mechanisms for multistability in a semiconductor laser. Study on optical injection locked semiconductor lasers. Cy i njection locking is a promising method to synchro. Modulation properties of an injectionlocked semiconductor laser. Injection seeding without frequency locking is often applied to qswitched lasers and to optical parametric oscillators, and sometimes incorrectly called injection locking. An optical carrier wave generated by a chaotic laser is used to encode a message for optical. Fabrication and characterization of edgeemitting semiconductor lasers dr. Injection locking of a semiconductor laser to a multi.
Strong optical injection locking of edgeemitting lasers. Selfinjection locking to an external fiber cavity is an ef. Chaotic dynamics of semiconductor lasers for secure optical communication 117 operating conditions of the laser. Numerical investigation into the injectionlocking phenomena. Modulation properties of solitary and optically injected. Properties and applications of injection locking in 1. The main result is the identification of four regimes for different injection levels. Based on the langkobayashi model, we perform an analysis of the wellknown low frequency fluctuations lffs in the frequencyintensity plane.
Injection locking of semiconductor lasers with the master and the slave monolithically integrated on the same substrate can be conveniently achieved with the whistlegeometry ring laser wrl proposed in chapter 3, which ensures strong injection. Mechanisms for multistability in a semiconductor laser with. Due to the high side mode suppression, these devices show different locking properties when compared to lasers having fabryperot structures. All optical 2r repeater9 and all optical 3r regeneration10. Semiconductor lasers subjected to external optical injection from a single mode tunable laser have been investigated in a masterslave con. Fromwx wx a theoretical point of view, a laser with optical injection is the simplest system with interesting dy.
The resulting dynamics has been studied by measuring the output of the slave laser as the frequency detuning between the lasers, the injection strength, and the slave laser current are varied. Injection locking, semiconductor laser, phase noise, dfb laser. Injection locking of semiconductor modelocked lasers for. Osa modulation properties enhancement in a monolithic. Wu, chair semiconductor lasers are essential components that enable highspeed longhaul. Strong optical injection locking of edgeemitting lasers and its applications by hyukkee sung doctor of philosophy in engineering electrical engineering and computer sciences university of california, berkeley professor ming c.
Role of dynamical injection locking and characteristic pulse. In section iv, the properties of an sl subject to external light injection from several lasers are investigated based on numerical analysis and experiments. Injection locking characteristics of indium arsenide quantum dash lasers by aaron moscho b. The processing techniques and properties are described here in the last decade the semiconductor injection laser has become a mature device for use in. Highly tunable repetitionrate multiplication of modelocked. In reality a semiconductor laser is simply a semiconductor diode, because its active medium is the junction of the forward biased pn diode, shown as. Erbiumdoped fibre lasers are of interest for optical fibre commu nications because they operate around 1. The lowfrequency rolloff in the moil dfb laser is suppressed significantly. At the same time, the linewidth of the dfb laser is reduced to below i. The injection direction influence is taken into account and the difference between front and rear phase noise is pointed out and demonstrated. We propose and demonstrate a unique optical signal inverter using injection locking in coupled semiconductor lasers with a narrowband fabryperot fp etalon.
This shift due to optical injection is effective for enhancing the modulation characteristics of semiconductor lasers. Reduction of frequency chirping and dynamic linewidth in highspeed directly modulated semiconductor laser by injection locking. Role of dynamical injection locking and characteristic. It enhances the intrinsic component bandwidth and reduces frequency chirp. Intensity and phase modulations im and pm are analyzed throughout the locking range where the locked laser is stable. This thesis focuses on the development of a semiconductor laser fabricating process which utilizes semiconductor manufacturing technology in a.
A phase preserving limiter based on injection locking in semiconductor lasers is experimentally investigated for 10gbs phase encoded signals. The term selfinjection locking is sometimes used for a technique which is somewhat related to the technique explained above. Tolerances for phase locking of semiconductor laser arrays e. Pdf we present the analysis of the selfinjection locking of a. On phase noise of selfinjection locked semiconductor lasers. Injection locking properties of a semiconductor laser ieee journals. Effects of noise on transients of injection locked. Optical injection locking is the coupling of light from the master laser into the resonant cavity of the slave laser in such a way that the slave output is captured by the master and becomes phase coherent with it. Here the metal contacts shown are used to connect the pn material to the dc power supply. At the junction light is emitted when electrons or current. Our analysis has shown that modal instabilities can occur in complexcoupled dfb lasers even though the initial side. Leisher the semiconductor laser was invented in 1962, and has recently become ubiquitous in modern life. Effects of noise on transients of injection locked semiconductor lasers marc r.
Injection locking of a semiconductor laser to a multifrequency reference beam t. Locking conditions and stability properties for a semiconductor laser with external light injection. The locking range is demonstrated by the vertical cyan lines, as well as the injection lock phase limits of. Semiconductor optoelectronics farhan rana, cornell university p p p p np n v the number of photons leaving the cavity from the mirrors is therefore, p p p o p p o n n v the output power p of the laser is.
Chaotic dynamics of semiconductor lasers for secure. Selfinjection locking of a laser diode to a highq wgm. In these lasers, the side longitudi nal modes are highly suppressed by the distributed grat. The dfb laser forces the fibre laser to oscillate in a nearly single longitudinal mode. The injection locking technique allows the lasers to exceed their fundamental modulation speed limit, allowing for greater communication speeds. Dynamics in semiconductor lasers with optical injection. In this paper, the possibility of improved modulation characteristics of injection locking semiconductor lasers is studied numerically. A unifying view of bifurcations in a semiconductor laser. Sidemode injection locking characteristics of 150 mw algaas.
Nonlinear dynamics of optically injected semiconductor lasers. It has been found that this dependence significantly affects the injection locking properties, giving rise to a peculiar asymmetric tuning curve and dynamic instability. In this paper we investigate coupled laser systems and focus on the modulation properties of aphased arrayconsisting of twosemi. Pdf injection locking is a well known and commonly used method for. Introduction injection locking is a particularly interesting method to reduce laser linewidth,1 enhance the modulation bandwidth,2 synchronize lasers for microwave generation3,4. The proposed scheme exhibits significant amplitude noise squeezing in conjunction with extreme simplicity. With injection locking, the bandwidth of the slave laser has been increased by nearly 60%.
Laser injection locking has been mainly used for amplification 38 and duplication 39,40,41,42 of lownoise laser oscillator. Strong optical injection locking of edgeemitting lasers and. A monolithic optical injectionlocked moil dfb laser with large stable injection locking range is experimentally demonstrated using the sidemode injection locking technique. The relaxation oscillation resonance in the im and pm frequency responses can be dramatically reduced by tuning the injected power and the. Oct 12, 2017 we investigate the dynamics of semiconductor lasers subject to timedelayed optical feedback from the perspective of dynamical self injection locking. Optical effects on the dynamical properties of semiconductor laser devices and their applications 4 songkun ji february 2019 list of figures figure 2.
We detail the injection locking behavior by examining the output spectra as the power of the injected master signal is increased. Experimental setup figure 1 gives a simplified schematic diagram of our injection locking experiment. However, the seed signal then comes from the same laser, rather than from an external seed laser. This paper reports, for the first time to the authors knowledge, a systematic experimental investigation of the injection locking properties of distributed feedback dfb semiconductor lasers. Demonstration of self injection locking of a fabryperot semiconductor laser operating at 690 nm. Theoretical analysis of optical injection locking in. Studies on the effective physical parameters for chirp. Factor in dfb semiconductor lasers by injection locking where bt 1 exp imt 4 is the normalised electric field of the slave laser sl and blt 1.
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